Mobile station, base station, transmission method and receiving method

ABSTRACT

In an operation in a license-exempt band (unlicensed band), the present invention contributes to the provision of a mobile station, a base station, a transmission method and a receiving method which suitably transmit and receive a signal. The mobile station  200  includes: a transmission unit  205  which transmits an uplink signal; and a control unit  201  which, when a first number indicating a first resource amount that can be used in the transmission of the uplink signal includes a third number, which is different from a specific second number, as a prime factor, controls the transmission of a signal of a fourth number that does not include the third number as the prime factor by using a second resource.

TECHNICAL FIELD

The present disclosure relates to a mobile station, a base station, atransmission method, and a reception method.

BACKGROUND ART

A communication system called a 5th generation mobile communicationsystem (5G) is now under study. An International Standardizing Body,3GPP (3rd Generation Partnership Project), is discussing sophisticationof the 5G communication system from the both the viewpoints of furtheradvancing LTE (Long Term Evolution) and LTE-A (LTE-Advanced) systems andof developing an NR (NEW RAT (New Radio access technology)) (see, forexample, Non-Patent Literature (NPL) 1) that is not always backwardcompatible with LTE and LTE-A.

Regarding to NR, studies targeting operation in an unlicensed band inaddition to a licensed band are carried out (see, for example, NPL 2) aswith LTE-LAA (License-Assisted Access). The operation in the unlicensedband is also referred to as, for example, NR-U (NR-based Access toUnlicensed Spectrum).

CITATION LIST Patent Literature

-   PTL 1-   Japanese Patent Application Laid-Open No. 2012-90013 Non-Patent    Literatures-   NPL 1-   RP-181726, “Revised WID on New Radio Access Technology”-   NPL 2-   RP-181339, “Revised SID on NR-based Access to Unlicensed Spectrum”-   NPL 3-   ETSI EN 301 893 V2.1.1-   NPL 4-   3GPP TS 38.101-1 V15.3.0-   NPL 5-   “Block-Interleaved Frequency Division Multiple Access and its    Application in the Uplink of Future Mobile Radio Systems”, T. Frank-   NPL 6-   “LTE for 4G Mobile Broadband”, F. Khan-   NPL 7-   3GPP TS 38.211 V15.3.0

SUMMARY OF INVENTION

With regard to the operation in the unlicensed band, however, methods oftransmitting and receiving signals are not yet sufficiently studied.

One non-limiting and exemplary embodiment facilitates providing a mobilestation, a base station, a transmission method, and a reception methodthat are able to appropriately transmit and receive signals in theoperation in the unlicensed band.

A mobile station according to one exemplary embodiment of the presentdisclosure includes: transmission circuitry, which, in operation,transmits an uplink signal; and control circuitry, which, in operation,when a first number indicating an amount of a first resource usable intransmitting the uplink signal includes, as a prime factor, a thirdnumber different from a specific second number, controls transmission ofa fourth number of signals, the transmission being performed using asecond resource, the fourth number not including the third number as aprime factor.

A base station according to one exemplary embodiment of the presentdisclosure includes: reception circuitry, which, in operation, receivesan uplink signal; and control circuitry, which, in operation, when afirst number indicating an amount of a first resource usable intransmitting the uplink signal includes, as a prime factor, a thirdnumber different from a specific second number, controls reception of afourth number of signals, the reception being performed using secondresources, the fourth number not including the third number as a primefactor.

A transmission method according to one exemplary embodiment of thepresent disclosure includes: configuring, when a first number indicatingan amount of a first resource usable in transmitting an uplink signalincludes, as a prime factor, a third number different from a specificsecond number, the fourth number not including the third number as aprime factor; and controlling transmission of the fourth number ofsignals, the transmission being performed using a second resource.

A reception method according to one exemplary embodiment of the presentdisclosure includes: configuring, when a first number indicating anamount of a first resource usable in transmitting an uplink signalincludes, as a prime factor, a third number different from a specificsecond number, a fourth number not including the third number as a primefactor; and controlling reception of the fourth number of signals, thereception being performed using a second resource.

A base station according to one exemplary embodiment of the presentdisclosure includes: reception circuitry, which, in operation, receivesan uplink signal; and control circuitry, which, in operation, decides afirst resource usable in transmitting the uplink signal, and controls areception process of the uplink signal, the reception process beingperformed using the first resource, in which: the first resource has oneor more bands positioned at a predetermined spacing among a plurality ofbands that are obtained by dividing a predetermined frequency band, andthe control circuitry configures the one or more bands in the firstresource such that a number indicating an amount of resource included inthe first resource does not include, as a prime factor, a third numberdifferent from a specific second number.

A mobile station according to one exemplary embodiment of the presentdisclosure includes: transmission circuitry, which, in operation,transmits a signal; and control circuitry, which, in operation, controlsa transmission process of the signal, the transmission process beingperformed using usable a first resource, in which: the first resourcehas one or more bands positioned at a predetermined spacing among aplurality of bands that are obtained by dividing a predeterminedfrequency band, at least part of the plurality of bands has a differentband width from remaining part, and a number indicating an amount ofresource included in the first resource does not include, as a primefactor, a third number different from a specific second number.

It should be noted that general or specific embodiments may beimplemented as a system, an apparatus, a method, an integrated circuit,a computer program, a storage medium, or any selective combinationthereof.

According to one exemplary embodiment of the present disclosure, signalscan be appropriately transmitted and received in the operation in theunlicensed band.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an example of an interlace configuration in LTE LAA;

FIG. 2 illustrates an example of an interlace configuration in NR-U;

FIG. 3 is a block diagram illustrating a configuration of part of a basestation according to Embodiment 1;

FIG. 4 is a block diagram illustrating a configuration of part of amobile station according to Embodiment 1;

FIG. 5 is a block diagram illustrating a configuration of the basestation according to Embodiment 1;

FIG. 6 is a block diagram illustrating a configuration of the mobilestation according to Embodiment 1;

FIG. 7 illustrates an example of an operation sequence between the basestation and the mobile station according to Embodiment 1;

FIG. 8 illustrates an example of allocation resources;

FIG. 9 illustrates another example of the interlace configuration inNR-U; and

FIG. 10 illustrates an example of an interlace configuration accordingto Other Embodiment 2.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure will be described in detail belowwith reference to the drawings.

As mentioned above, the studies targeting the operation of the NR systemin the unlicensed band (for example, a frequency band lower than 7 GHz)are carried out.

With respect to the unlicensed band, an upper limit value of PowerSpectral Density (hereinafter also referred to as PSD in some cases) isrestricted by the laws, the standards, and so on. For example, accordingto the standards stipulated by ETSI (European TelecommunicationsStandards Institute) (see, for example, NPL 3), the upper limit value ofPSD in the so-called 5 GHz band is configured to, for example, 10dBm/MHz (17 dBm/MHz in some bands) even for a terminal with the powercontrol function.

In order to transmit signals with higher transmission power under thelimitation on PSD, it is effective to arrange resources to bedistributed in the frequency domain. From that point of view, anallocation technique called an interlace allocation is considered inNR-U.

According to the allocation technique called the interlace allocation, acertain band (for example, 20 MHz) is divided into a plurality ofinterlaces. An interlace includes, for example, a plurality ofconsecutive sub-carrier groups. One consecutive sub-carrier groupcorresponds to, for example, one Physical Resource Block (hereinafteralso referred to as PRB in some cases). The plurality of consecutivesub-carrier groups are arrayed at equal spacings or unequal spacings inthe frequency domain. In other words, each interlace includes aplurality of PRBs arrayed at equal spacings or unequal spacings in thefrequency domain.

For example, different interlaces include different resources. Thus, theresources do not overlap with each other between different interlaces.Furthermore, different identifiers are assigned to the differentinterlaces. The identifiers assigned to the interlaces are also referredto as interlace numbers in some cases.

The allocation technique called the interlace allocation is used in, forexample, an uplink. A base station (hereinafter also referred to as, forexample, Base Station, Node B, or gNB in some cases) is supposed toindicate one or multiple interlace numbers to a mobile station(hereinafter also referred to as, for example, a terminal or UE (UserEquipment) in some cases). In such a case, the mobile station issupposed to assign signals to the resources corresponding to eachindicated interlace number and to transmit the assigned signals.

FIG. 1 illustrates an example of an interlace configuration in LTE LAA.In the example of FIG. 1, a band of 20 MHz is divided into 10interlaces. Interlace numbers 0 to 9 are assigned respectively to the 10interlaces. In the following description, the interlace with the numberi (i is an integer larger than or equal to 0) is also denoted by the“interlace #i” in some cases.

Each interlace includes PRBs arrayed at equal spacings in the frequencydomain. A number put in each PRB indicates the interlace number. Theinterlaces with different numbers in no way include the same PRB.

According to NR, it is considered to configure, in a band of 20 MHzincluded in a frequency band lower than 6 GHz, a maximum PRB allocationnumber to 106, 51, and 24 respectively for subcarrier spacings(hereinafter also referred to as SCSs in some cases) of 15 kHz, 30 kHz,and 60 kHz (see, for example, NPL 4). The maximum PRB allocation numberconsidered in NR is a different value from the maximum PRB allocationnumber (namely, 100) in LTE.

With regard to the NR system in the unlicensed band (for example, afrequency band lower than 7 GHz), an interlace configuration isconsidered on the basis of the above-mentioned maximum PRB allocationnumber.

For example, 3GPP is discussing about a plurality of combinations of Mand N on condition that the band of 20 MHz is divided into a number M ofinterlaces and each of the M interlaces includes a number N of PRBs. Mand N are examples of parameters representing the interlaceconfiguration. Furthermore, it is discussed that, when the maximum PRBallocation number is not a multiple of M, the number of PRBs included ina certain interlace is configured to be larger than the maximum PRBallocation number included in the other interlaces by one.

For example, the discussion is carried out on the case of configuring Mto 12 when the subcarrier spacing is 15 kHz. When the subcarrier spacingis 15 kHz, the maximum PRB allocation number is 106 and 106 is not amultiple of M=12. Therefore, it is discussed to, when the subcarrierspacing is 15 kHz and M is 12, configure the interlaces such that someinterlaces each include 9 PRBs and the other interlaces each include 8PRBs.

In order to suppress PAPR (Peak to Average Power Ratio) of transmittedsignals in an uplink, the mobile station is supposed to perform a DFT(Discrete Fourier Transform) process on the transmitted signals (see,for example, NPL 5). In such a case, the mobile station is supposed toperform mapping of the signal after the DFT process to the resources ofinterlaces. Moreover, when the mobile station transmits the signalsafter the DFT process, the base station is supposed to perform an IDFT(Inverse Discrete Fourier Transform) process in a reception process.

Regarding the DFT process using FFT (Fast Fourier Transform), it isknown that an amount of computation reduces when a DFT size can befractionized into relatively small prime numbers (see, for example, NPL6). The DFT size corresponds to, for example, the number of outputsafter the DFT process. Furthermore, regarding the IDFT process usingIFFT (Inverse Fast Fourier Transform), it is known that an amount ofcomputation reduces when an IDFT size similar to the DFT size can befractionized into relatively small prime numbers. Taking the above pointinto account, one example of conditions is specified such that, when asignal waveform based on DFT-S-OFDM (DFT-Spread-Orthogonal FrequencyDivision Multiplexing) is used in the uplink of the NR system, thenumber of subcarriers allocated to the mobile station is a numberincluding at least one prime factor among 2, 3 and 5 (see, for example,NPL 7). In other words, it is specified as a condition that the numberof the subcarriers allocated to the mobile station is a number notincluding any prime factor different from 2, 3 and 5.

In LTE LAA operating the LTE system in the unlicensed band, because thecombination of the numbers of M and N representing the interlaceconfiguration is (M, N)=(10, 10) or (M, N)=(10, 5), the number of PRBsallocated to the mobile station is a multiple of 10. Thus, the number ofallocated subcarriers is a multiple of 120. Here, because 120 does notinclude any prime factor different from 2, 3 and 5, the above-describedcondition can be relatively easily satisfied in LTE LAA.

In the interlace configuration that is an item under consideration inNR-U, the number of the allocated subcarriers may include a prime factordifferent from 2, 3 and 5. Such a point is described below in connectionwith an example in which the subcarrier spacing is 15 kHz and thecombination of the numbers of M and N representing the interlaceconfiguration is (M, N)=(12, 8 or 9).

The combination of M and N representing the interlace configuration,which is the item under consideration in NR-U, is not limited to (M,N)=(12, 8 or 9). For example, when the subcarrier spacing is 15 kHz, thecombination of the numbers of M and N representing the interlaceconfiguration may be (M, N)=(10, 10 or 11) or (M, N)=(8, 13 or 14). Whenthe subcarrier spacing is 30 kHz, the combination of the numbers of Mand N representing the interlace configuration may be (M, N)=(6, 8 or9), (M, N)=(5, 10 or 11), or (M, N)=(4, 12 or 13). When the subcarrierspacing is 60 kHz, the combination of the numbers of M and Nrepresenting the interlace configuration may be (M, N)=(4, 6), (M,N)=(3, 8), or (M, N)=(2, 12). Furthermore, when the subcarrier spacingis 60 kHz and 26 PRBs are included in a band width of 20 MHz, thecombination of the numbers of M and N representing the interlaceconfiguration may be (M, N)=(4, 6 or 7), (M, N)=(2, 13), or (M, N)=(3, 8or 9).

FIG. 2 illustrates an example of an interlace configuration in NR-U. Inthe example of FIG. 2, the interlace of N=8 (namely, the interlaceincluding 8 PRBs) and the interlace of N=9 (namely, the interlaceincluding 9 PRBs) may be both allocated to the mobile station in somecases.

For example, when one interlace of N=8 and one interlace of N=9 areallocated to the mobile station, the number of PRBs allocated to themobile station is 17, and hence the number of subcarriers allocated tothe mobile station is 204. Because 204 includes a relatively large primefactor 17, there is a possibility that the amount of computationexecuted in the DFT process increases, when the mobile station performsthe DFT process of signals for which mapping to the 204 subcarriers isto be performed. Moreover, there is a possibility that the amount ofcomputation executed in the IDFT process increases as in the DFTprocess, when the base station performs the IDFT process of the signalsfor which the mapping to the 204 subcarriers has been performed by themobile station.

The present disclosure is described below in connection with an exampleof the technique with which resources can be efficiently utilizedwithout increasing the amount of computation executed in each of a DFTprocess and an IDFT process corresponding to the DFT process.

Embodiment 1 [Outline of Communication System]

A communication system according to an embodiment of the presentdisclosure includes base station 100 and mobile station 200. In thefollowing description, by way of example, base station 100 determinesresources to be allocated to mobile station 200 and indicatesinformation indicating the determined resources. In accordance with theindication, mobile station 200 performs a signal transmission processincluding a process for mapping to the resources and transmits signalsto base station 100.

FIG. 3 is a block diagram illustrating a configuration of part of basestation 100 according to Embodiment 1 of the present disclosure. In basestation 100 illustrated in FIG. 3, receiver 106 receives an uplinksignal, and when a first number indicating an amount of a first resourceusable to transmit the uplink signal includes, as a prime factor, athird number different from a specific second number, controller 101controls reception of a fourth number of signals, the reception beingperformed using a second resource, the fourth number not including thethird number as a prime factor.

FIG. 4 is a block diagram illustrating a configuration of part of themobile station 200 according to Embodiment 1 of the present disclosure.In mobile station 200 illustrated in FIG. 4, transmitter 205 transmitsthe uplink signal, and when the first number indicating the amount ofthe first resource usable to transmit the uplink signal includes, as aprime factor, the third number different from the specific secondnumber, controller 201 controls transmission of the fourth number ofsignals, the transmission being performed using the second resource, thefourth number not including the third number as a prime factor.

[Configuration of Base Station]

FIG. 5 is a block diagram illustrating a configuration of the basestation 100 according to Embodiment 1.

In FIG. 5, base station 100 includes controller 101, encoder/modulator102, signal assigner 103, transmitter 104, antenna 105, receiver 106,signal separator 107, IDFT (Inverse Discrete Fourier Transform) section108, and demodulator/decoder 109.

For example, controller 101 schedules the uplink and determines theresources that are allocated to mobile station 200. Controller 101outputs allocation resource information (for example, an interlacenumber assigned to uplink transmission for mobile station 200) toencoder/modulator 102 and signal assigner 103. The allocation resourceinformation output to signal assigner 103 may be included in, forexample, DCI (Downlink Control Information). The allocation resourceinformation output to encoder/modulator 102 may be included in, forexample, a higher layer signal.

When a number indicating an amount of resources having been allocated tomobile station 200 includes a prime factor different from one or morespecific numbers, controller 101 controls a reception process on anassumption that the resources to which the uplink signals received frommobile station 200 are mapped and the resources having been allocated tomobile station 200 are different from each other.

Although the following description is made in connection with an examplein which the uplink signals are data signals including uplink data, theuplink signals in the present disclosure may include signals differentfrom the data signals.

Here, the number indicating the amount of resource is, for example, thenumber of subcarriers included in the resources. The specific numbersare relatively small prime number such as 2, 3 and 5, for example. Thewording that the resources to which the data signals are mapped aredifferent from the allocated resources correspond to, for example, asituation in which the number and/or the positions of subcarriers towhich the data signals are mapped are different from the number and/orthe positions of allocated subcarriers. Moreover, the wording that theresources to which the data signals are mapped are different from theallocated resources may include a situation in which the number ofreceived data signals is different from the number of data signalsreceivable in the allocated resources.

The number indicating the amount of resource is not limited to thenumber of subcarriers. The number indicating the amount of resource maybe, for example, the number of subcarrier groups or the number of PRBs.The specific numbers are not limited to 2, 3 and 5. The specific numbersmay include a prime number different from 2, 3 and 5, or at least one of2, 3 and 5 may be excluded from the specific numbers.

For example, when the number of the allocated subcarriers includes aprime factor different from the specific numbers, controller 101 maychange at least one among the number and the positions of thesubcarriers to which the data signals are mapped and the number of thedata signals to a value different from that for the allocated resources.For example, controller 101 may change at least one among the number andthe positions of the subcarriers and the number of the data signals,which are included in the allocation resource information. Informationafter being changed indicates the number of the resources to which thedata signals are to be mapped and/or the number of uplink data signalsto be transmitted from mobile station 200. In another example, thenumber of the data signals after being changed may be the number of thedata signals to be output from IDFT section 108. In the followingdescription, the information after being changed is also referred to asmapping resource information in some cases. Controller 101 outputs themapping resource information to signal separator 107. Furthermore,controller 101 outputs the information about the number of the uplinkdata signals to IDFT section 108.

Encoder/modulator 102 receives the higher layer signal as an input andexecutes error correction coding and modulation on the input higherlayer signal. Encoder/modulator 102 outputs signals after the errorcorrection coding and the modulation to signal assigner 103.

Signal assigner 103 arranges (maps) the signals obtained fromencoder/modulator 102 and/or DCI obtained from controller 101 toresources that are specified in the time domain and the frequencydomain. Signal assigner 103 outputs the mapped signals to transmitter104.

Transmitter 104 executes a radio transmission process, such as frequencyconversion (for example, up conversion) using a carrier wave, on thesignals received from signal assigner 103 and outputs the signals afterthe radio transmission process to antenna 105.

Antenna 105 radiates the signals (downlink signals) received fromtransmitter 104 toward mobile station 200. In addition, antenna 105receives the uplink signals transmitted from mobile station 200 andoutputs the received uplink signals to receiver 106.

Receiver 106 executes a radio reception process, such as frequencyconversion (for example, down conversion), on the signals received fromantenna 105 and outputs the signals after the radio reception process tosignal separator 107.

Signal separator 107 extracts, in accordance with the mapping resourceinformation received from controller 101, the data signals included inthe signals that have been received from receiver 106. For example,signal separator 107 specifies, in accordance with the mapping resourceinformation, the resource positions specified in the time domain and thefrequency domain, and then extracts the data signals mapped to thespecified positions. Signal separator 107 outputs the extracted datasignals to IDFT section 108.

IDFT section 108 executes an IDFT process (for example, an IFFT process)on the data signals received from signal separator 107. IDFT section 108outputs the data signals after the IDFT process to demodulator/decoder109. When the number of the data signals received from signal separator107 is different from the number of the data signals which is indicatedby the information received from controller 101, IDFT section 108 mayexecute a signal interpolation process or a signal thinning process inthe IDFT process. In such a case, the number of the signals output fromIDFT section 108 may be the same as the number of the data signals whichis indicated by the information received from controller 101.

Demodulator/decoder 109 demodulates and decodes the data signalsreceived from IDFT section 108.

[Configuration of Mobile Station]

FIG. 6 is a block diagram illustrating a configuration of the mobilestation 200 according to Embodiment 1.

In FIG. 6, mobile station 200 includes controller 201, encoder/modulator202, DFT section 203, signal assigner 204, transmitter 205, antenna 206,receiver 207, signal separator 208, and demodulator/decoder 209.

Controller 201 obtains information (for example, the above-describedallocation resource information) indicating uplink resources that havebeen allocated to mobile station 200 by base station 100, and controls atransmission process for the uplink signals. For example, controller 201outputs, in accordance with the DCI received from signal separator 208and/or the higher layer signal received from demodulator/decoder 209,the information indicating the uplink resources, which have beenallocated to mobile station 200, to encoder/modulator 202 and/or signalassigner 204.

For example, when the number indicating the amount of the resourceshaving been allocated to mobile station 200 includes a prime factordifferent from the specific numbers, controller 201 controls thetransmission process on an assumption that the resources having beenallocated to mobile station 200 and the resources to which the datasignals are mapped are different from each other.

For example, when the number of the allocated subcarriers includes aprime factor different from the specific numbers, controller 201 maychange at least one among the number and the positions of thesubcarriers to which the data signals are mapped and the number of thedata signals to a value different from that for the allocated resources.For example, controller 201 may change at least one among the number andthe positions of the subcarriers and the number of the data signals,which are included in the allocation resource information. Information(above-described mapping resource information) after being changedindicates the number of the resources to which the data signals are tobe arranged (mapped) and/or the number of uplink data signals to betransmitted. In another example, the number of the data signals afterbeing changed may be the number of the data signals to be output fromDFT section 203 or the number of the data signals to be input to DFTsection 203. Controller 201 outputs the mapping resource information tosignal assigner 204. Furthermore, controller 201 outputs the informationabout the number of the uplink data signals to encoder/modulator 202.

Antenna 206 receives the downlink signals transmitted from base station100 and outputs the received downlink signals to receiver 207. Inaddition, antenna 206 radiates the uplink signals received fromtransmitter 205 toward base station 100.

Receiver 207 executes a radio reception process, such as frequencyconversion (for example, down conversion), on the signals received fromantenna 206 and outputs the signals after the radio reception process tosignal separator 208.

Signal separator 208 extracts downlink data signals and/or controlinformation (for example, DCI), et., which are included in the downlinksignals that have been received from receiver 207. For example, signalseparator 208 specifies the resource positions to which the downlinkdata signals and/or the control information has been mapped, and thenextracts the downlink data signals and/or the control signal mapped tothe specified positions. Signal separator 208 outputs the downlink datasignals to demodulator/decoder 209 and further outputs the controlinformation to controller 201.

Demodulator/decoder 209 demodulates and decodes the downlink datasignals received from signal separator 208. Demodulator/decoder 209outputs the decoded signal (higher layer signal) to the controller 201.

Encoder/modulator 202 executes error correction coding and modulation onthe uplink data in accordance with the information about the number ofthe data signals, which has been received from controller 201, andoutputs the resulting signals to DFT section 203.

DFT section 203 executes a DFT process (for example, a FFT process) onthe signals received from encoder/modulator 202 and outputs the datasignals to signal assigner 204.

Signal assigner 204 maps, in accordance with the resource mappinginformation received from controller 201, the data signals received fromDFT section 203 to the time domain and the frequency domain. Signalassigner 204 outputs the mapped signals to the transmitter.

Transmitter 205 executes a radio transmission process, such as frequencyconversion (for example, up conversion) using a carrier wave, on thesignals received from signal assigner 204 and outputs the signals afterthe radio transmission process to antenna 206.

An example of an operation sequence between base station 100 and mobilestation 200 will be described below.

FIG. 7 illustrates an example of the operation sequence between basestation 100 and mobile station 200 according to Embodiment 1.

In the following description, the resources allocated to mobile station200 by base station 100 are also referred to as “allocation resource” insome case. The resources to which the uplink data signals are mapped bymobile station 200 are also referred to as “mapping resource” in somecase. Furthermore, when the resources are represented by thesubcarriers, the allocation resource and the mapping resource arereplaced respectively with “allocation subcarrier” and “mappingsubcarrier” in some cases.

Base station 100 decides one or more interlace numbers that are assignedto mobile station 200 (ST101).

Base station 100 indicates information (allocation resource information)including the decided interlace numbers to mobile station 200 by usingthe higher layer signal and/or DCI (ST102).

Mobile station 200 determines whether the number of the allocationsubcarriers, which has been decided in accordance with the indication,includes a prime factor different from the specific numbers (ST103).

If the number of the allocation subcarriers does not include any primefactor different from the specific numbers (NO in ST103), mobile station200 executes a process of ST105.

If the number of the allocation subcarriers includes a prime factordifferent from the specific numbers (YES in ST103), mobile station 200adjusts a size of data signals to be transmitted and/or resources towhich the data signals are mapped (ST104). The adjustment of the size ofthe transmitted data signals may be performed by, for example, adjusting(changing) the number of the transmitted data signals. The adjustment ofthe resources to which the data signals are mapped may be performed by,for example, adjusting (changing) an amount of the resources to whichthe data signals are mapped and/or the positions of those resources.Furthermore, as described above, the resources to which the data signalsare mapped may correspond to the mapping resources. Then, mobile station200 executes a process of ST105.

Mobile station 200 arranges (maps) the data signals to the resources(ST105).

After the process of ST102, base station 100 determines whether thenumber of the allocation subcarriers includes a prime factor differentfrom the specific numbers (ST106).

If the number of the allocation subcarriers does not include any primefactor different from the specific numbers (NO in ST106), base station100 executes a reception process of ST108.

If the number of the allocation subcarriers includes a prime factordifferent from the specific numbers (YES in ST106), base station 100adjusts a size of data signals to be received and/or resources to whichthe received data signals have been mapped (ST107). The adjustment ofthe size of the received data signals may be performed by, for example,adjusting (changing) the number of the received data signals. Theadjustment of the resources to which the data signals have been mappedmay be performed by, for example, adjusting (changing) an amount of theresources to which the data signals have been mapped and/or thepositions of those resources. Furthermore, as described above, theresources to which the data signals have been mapped may correspond tothe mapping resources. Then, base station 100 executes the receptionprocess of ST108.

Mobile station 200 transmits the uplink signals, and base station 100receives the uplink signals (ST108).

Although FIG. 7 illustrates an example in which base station 100executes the process of ST106 after ST102 and further executes theprocess of ST107 in the case of YES in ST106, base station 100 mayexecute the process of ST106 between ST101 and ST102 and furtherexecutes the process of ST107 in the case of YES in ST106. In such amodified example, base station 100 may indicate information (forexample, the mapping resource information) after the adjustment in ST107to mobile station 200 in ST102 by using the higher layer signal and/orDCI. In that example, mobile station 200 is no longer required toexecute the processes of ST103 and ST104.

The following description is made in connection with examples ofconfiguring the resources, which are allocated to mobile station 200, bybase station 100, and with examples of configuring the resources towhich the data signals are mapped by mobile station 200.

[First Example of Allocation Resources and Mapping Resources]

An example of deciding the resources, which are allocated to mobilestation 200, by the base station and an example of deciding theresources to which the data signals are mapped by mobile station 200 aredescribed, by way of example, in connection with the case in which thesubcarrier spacing is 15 kHz and the interlace configuration is given byM=10 and N=8 or 9.

The interlace configuration in the case of M=10 and N=8 or 9 oncondition of the subcarrier spacing being 15 kHz is as per illustratedin FIG. 2, for example.

Controller 101 decides one or more interlace numbers in theconfiguration illustrated in FIG. 2 and further decides, as theallocation resources, the resources (for example, PRBs) corresponding tothe decided interlace numbers.

FIG. 8 illustrates an example of the allocation resources. In theexample of FIG. 8, an interlace #0 and an interlace #10 are assigned tomobile station 200. The interlace #0 is an interlace of N=9 (namely, aninterlace including 9 PRBs), and the interlace #10 is an interlace ofN=8 (namely, an interlace including 8 PRBs).

In the above-mentioned case, base station 100 indicates the allocationresource information, indicating that the allocation resource are theinterlace #0 and the interlace #10, to mobile station 200 by using DCIand/or the higher layer signal.

In accordance with the obtained allocation resource information,controller 201 in mobile station 200 decides that the allocationresources are the interlaces #0 and #10. Then, controller 201 decides aresource amount of the allocation resources. For example, when theresource amount is expressed by the number of subcarriers, controller201 decides the number of the allocation subcarriers. For example,because the number of PRBs belonging to the interlace #0 is 9, thenumber of PRBs belonging to the interlace #10 is 8, and one PRB includes12 subcarriers, controller 201 decides that the number of the allocationsubcarriers is 204.

Then, controller 201 determines whether the number of the allocationsubcarriers includes a prime factor different from the specific numbers.In the case in which the specific numbers are 2, 3 and 5, for example,because the number of the allocation subcarriers is 204=2×2×3×17,controller 201 determines that the number of the allocation subcarriersincludes a prime factor, namely 17, different from 2, 3 and 5.

In the above-mentioned case, controller 201 may change at least oneamong the number and the positions of the mapping subcarriers and thenumber of the data signals to a value different from that in theallocation resource information.

For example, controller 201 may configure, as the number of the datasignals output from DFT section 203, any one of numbers that are smallerthan or equal to the number of the allocation subcarriers (or smallerthan the number of the allocation subcarriers) and that do not includeany prime factor different from the specific numbers (namely, thatinclude only the specific numbers as prime factors thereof).Incidentally, controller 201 may configure the number of the mappingsubcarriers to be the same as the configured number of the data signals.

For example, a maximum one among numbers that are smaller than or equalto the number of the allocation subcarriers and that do not include anyprime factor different from the specific numbers may be configured tothe same as the number of the data signals and the number of the mappingsubcarriers.

In the case of the above-described example, the number of the allocationsubcarriers is 204 and the specific numbers are 2, 3 and 5. In thatcase, the maximum one among the numbers that are smaller than or equalto the number of the allocation subcarriers and that do not include anyprime factor different from the specific numbers is 200 (=2³×5²).

In the above-described case, controller 201 configures the number of thedata signals and the number of the mapping subcarriers to 200.

Instead, controller 201 may configure, as the number of the data signalsand the number of the mapping subcarriers, a number smaller than themaximum one among the numbers that are smaller than or equal to thenumber of the allocation subcarriers and that do not include any primefactor different from the specific numbers. For example, controller 201may configure the number of the data signals and the number of themapping subcarriers to 180 (=2²×3²×5) or 150 (=2×3×5²).

Then, controller 201 configures the positions of the mapping subcarriersamong the allocation subcarriers. A method of configuring the positionsof the mapping subcarriers is not limited to a particular one. Forexample, any suitable one of Configuring Method 1 to Configuring Method5, described below, may be used.

<Configuring Method 1>

For example, controller 201 may configure, as the mapping subcarriers,those ones among the allocation subcarriers, which are located on thehigher frequency side. In such a case, 200 subcarriers located on thehigher frequency side among the 204 subcarriers are configured as themapping subcarriers, and 4 subcarriers located on the lower frequencyside are not configured as the mapping subcarriers. Stated in anotherway, 4 subcarriers located on the lower frequency side are excluded.

<Configuring Method 2>

For example, controller 201 may configure, as the mapping subcarriers,those ones among the allocation subcarriers, which are located on thelower frequency side. In such a case, 200 subcarriers located on thelower frequency side among 204 subcarriers are configured as the mappingsubcarriers, and 4 subcarriers located on the higher frequency side arenot configured as the mapping subcarriers.

<Configuring Method 3>

For example, controller 201 may configure, as the mapping subcarriers,those ones among the allocation subcarriers except for the subcarrierslocated on both the lower frequency side and the higher frequency side.In such a case, 200 among the 204 subcarriers except for 2 subcarrierslocated on the higher frequency side and 2 subcarriers located on thelower frequency side are configured as the mapping subcarriers. Thenumber of subcarriers excluded on each of the higher frequency side andthe lower frequency side is not limited to a particular value. In theabove-described case, for example, 1 subcarrier located on the higherfrequency side and 3 subcarriers located on the lower frequency side maybe excluded.

According to Configuring Methods 1 to 3, the mapping subcarriers areconfigured on at least one of the higher frequency side and the lowerfrequency side among the allocation subcarriers. With those methods, thefrequency spacing between PRBs making up the mapping resources can bemaintained in a uniform state, and degradation of PAPR of the uplinksignals can be suppressed. Furthermore, interference from an adjacentband can be suppressed on the side where the mapping resources (mappingsubcarriers) are not configured.

<Configuring Method 4>

For example, controller 201 may configure, as the mapping subcarriers,those ones among the allocation subcarriers except for the subcarrierslocated in a central region. The subcarriers located in the centralregion may be, for example, any subcarriers different from thesubcarriers located on each of the higher frequency side and the lowerfrequency side. In other words, when those ones among the allocationsubcarriers except for the subcarriers located in the central region areconfigured as the mapping subcarriers, the highest frequency and thelowest frequency of the mapping subcarriers are not changed from thoseof the allocation subcarriers.

According to Configuring Method 4, those ones among the allocationsubcarriers except for the subcarriers located in the central region areconfigured as the mapping subcarriers. With this method, since OccupiedChannel Bandwidth (OCB) of the mapping subcarriers does not becomenarrower than the band of the allocation subcarriers, a possibility ofviolating the limitation stipulated by ETSI on OCB can be reduced.

<Configuring Method 5>

For example, controller 201 may configure, as the mapping subcarriers,those ones among the allocation subcarriers except for the subcarriersincluded in a specific interlace. In the case of the above-describedexample, among 108 subcarriers included in the interlace #0 and 96subcarriers included in the interlace #10, the subcarriers except for 4subcarriers included in the interlace #0 may be configured as themapping subcarriers. Instead, the subcarriers except for 4 subcarriersincluded in the interlace #10 may be configured as the mappingsubcarriers. On that occasion, a method of selecting the specificinterlace from which the subcarriers are to be excluded is not limitedto a particular one. For example, the interlace including the smallernumber of subcarriers before the exclusion of some subcarriers may bepreferentially selected. In the case of the above-described example,among 108 subcarriers included in the interlace #0 and 96 subcarriersincluded in the interlace #10, 4 subcarriers included in the interlace#10 may be preferentially excluded and the remaining subcarriers may beconfigured as the mapping subcarriers.

According to Configuring Method 5, since Occupied Channel Bandwidth(OCB) of the mapping subcarriers can be ensured by the interlace towhich the excluded subcarriers do not belong, the possibility ofviolating the limitation stipulated by ETSI on OCB is low. For example,the possibility of violating the limitation stipulated by ETSI on OCBcan be further reduced by selecting, as the specific interlace fromwhich some subcarriers are to be excluded, the interlace including thesmaller number of subcarriers before the exclusion of the somesubcarriers. In addition, the frequency spacing between PRBs making upthe mapping resources can be maintained in a uniform state, anddegradation of PAPR of the uplink signals can be suppressed.

Controller 201 decides the number and the positions of the mappingsubcarriers and outputs, to signal assigner 204, the mapping resourceinformation including information that indicates the decided number andpositions of the subcarriers. Moreover, controller 201 outputs thenumber of the uplink data signals to encoder/modulator 202.

Encoder/modulator 202 executes error correction coding and modulation onthe uplink data in accordance with the number of the data signals andoutputs the resulting signals to DFT section 203. DFT section 203executes a DFT process (for example, a FFT process) on the signals thathave been received from encoder/modulator 202 and that are the same innumber as the data signals, and outputs the resulting output signals tosignal assigner 204. Here, since the number of the data signals is anumber not including any prime factor different from the specificnumbers (2, 3 and 5 in the above-described example), it is possible tosuppress an increase in the amount of computation executed in the DFTprocess (for example, the FFT process) by DFT section 203, and toincrease the speed of the DFT process.

Signal assigner 204 maps the signals, received from DFT section 203, inaccordance with the positions of the mapping subcarriers. On thatoccasion, signal assigner 204 does not need to map the signals to thesubcarriers different from the mapping subcarriers.

As with controller 201 in mobile station 200, controller 101 in basestation 100 may change at least one among the number and the positionsof the mapping subcarriers and the number of the data signals to a valuedifferent from that in the allocation resource information. Informationabout a changing method may be shared between mobile station 200 andbase station 100. In such a case, mobile station 200 and base station100 may change at least one among the number and the positions of themapping subcarriers and the number of the data signals to a valuedifferent from that in the allocation resource information in accordancewith the same changing method.

For example, IDFT section 108 executes an IDFT process (for example, aFFT process) on the signals that have been received from signalseparator 107 and that are the same in number as the data signals, andoutputs the processed signals to demodulator/decoder 109. Here, sincethe number of the data signals is a number not including any primefactor different from the specific numbers (2, 3 and 5 in theabove-described example), it is possible to suppress an increase in theamount of computation executed in the IDFT process (for example, theIFFT process) by IDFT section 108, and to increase the speed of the IDFTprocess.

In the above-described example, the frequency utilization efficiency ofthe allocation resources can be improved and flexible mapping of thedata signals can be realized by deciding the numbers of the data signalsand the mapping resources in units of subcarriers. For example, signalsdifferent from the uplink data signals may be mapped to resources thatare not configured as the mapping resources.

The unit used to express the numbers of the data signal and the mappingresources is not limited to subcarrier. For example, the numbers of thedata signal and the mapping resources may be decided in units ofsub-PRBs each of which includes the smaller number of subcarriers thanPRB (namely, subcarriers smaller than 12). It is to be noted thatsub-PRB may be referred to as part of PRB or may be regarded ascorresponding to another expression.

Instead, the numbers of the data signal and the mapping resources may bedecided in units of PRBs. The following description is made inconnection with a second example in which the numbers of the data signaland the mapping resources are decided in units of PRB s.

[Second Example of Allocation Resources and Mapping Resources]

When the numbers of the data signal and the mapping resources aredecided in units of PRBs, controller 201 decides any one of numbers thatare K times 12 (K is an integer larger than or equal to 1) among numbersbeing smaller than or equal to the number of the allocation subcarriersand not including any prime factor different from the specific numbers.Here, 12 is the number of subcarriers included in one PRB. Then,controller 201 configures K corresponding to the decided number as thenumber of PRBs for the mapping resources.

For example, when the mapping resources are decided with respect to theallocation resources illustrated in FIG. 8 as in the above-describedexample, controller 201 configures, on condition of K=16, 192=K times 12as the number of the data signals and configures K=16 as the number ofPRBs making up the mapping resources.

Controller 201 then decides the positions of the mapping resourcescorresponding to the configured number of PRBs making up the mappingresources.

As with Configuring Method 1 in the case of configuring the positions ofthe mapping resources in units of subcarriers, the positions of themapping resources may be configured to PRBs located on the higherfrequency side among the allocation resources in units of PRBs. Instead,as with Configuring Method 2 in the case of configuring the positions ofthe mapping resources in units of subcarriers, the positions of themapping resources may be configured to PRBs located on the lowerfrequency side among the allocation resources in units of PRBs.

For example, when the number of PRBs making up the mapping resources isconfigured to 16 in the example of FIG. 8, controller 201 may configure,as PRBs making up the mapping resources, 16 PRBs except for one PRB thatis included in the interlace #0 and that is given with the lowestfrequency. Instead, controller 201 may configure, as PRBs making up themapping resources, 16 PRBs except for one PRB that is included in theinterlace #0 and that is given with the highest frequency.

Furthermore, as with Configuring Method 3 in the case of configuring thepositions of the mapping resources in units of subcarriers, the mappingresources may be configured to some PRBs among the allocation resourcesin units of PRBs except for PRBs located on the higher frequency sideand PRBs located on the lower frequency side. Instead, as withConfiguring Method 4 in the case of configuring the positions of themapping resources in units of subcarriers, the mapping resources may beconfigured to some PRBs among the allocation resources in units of PRBsexcept for PRBs located in a central region. PRBs located in the centralregion may be, for example, some PRBs different from PRBs located on thehigher frequency side and from PRBs located on the lower frequency side.Instead, as with Configuring Method 5 in the case of configuring thepositions of the mapping resources in units of subcarriers, the mappingresources may be configured to PRBs among the allocation resources inunits of PRBs except for PRBs included in a specific interlace.

Also in the case of deciding the mapping resources in unit of PRBs, thefrequency spacing between PRBs making up the mapping resources can bemaintained in a uniform state, and degradation of PAPR of the datasignals can be suppressed as in the case of deciding the mappingresources in unit of subcarriers. Furthermore, interference from anadjacent band can be suppressed on the side where the mapping resourcesare not configured.

In the case of deciding the mapping resources in unit of PRBs, since theresources used for the transmission in mobile station 200 is decided inunits of PRBs, installation to mobile station 200 and base station 100can be facilitated.

According to Embodiment 1, as described above, mapping subcarriers in anumber not including any prime factor different from one or morespecific numbers (2, 3 and 5 in the above-described example) areselected from among the allocation subcarriers, and the data signals inthe same number as the selected mapping subcarriers are mapped to thosemapping subcarriers with a one-to-one correspondence. It is hencepossible to suppress an increase in the amounts of computations executedin the DFT process and the IDFT process corresponding to the DFTprocess, and to efficiently utilize the resources. As a result, signalscan be appropriately transmitted and received in the operation in theunlicensed band.

Embodiment 2

Embodiment 1 has been described in connection with the example in whichthe number of the uplink data signals and the mapping resources aredecided with respect to the allocation resources and the data signalsare mapped to the mapping subcarriers in the same amount as the datasignals with a one-to-one correspondence. Embodiment 2 is describedbelow in connection with an example in which a method of mapping theuplink data signals is changed with respect to the allocation resources.

An outline of a communication system, a configuration of a base station,a configuration of a mobile station, and an operation sequence inEmbodiment 2 are similar to those in Embodiment 1, and hence detaileddescription of those points is omitted. In the following, Embodiment 2is described by referring to the outline of the communication system,the configuration of the base station, and the configuration of themobile station, which have been described in Embodiment 1.

In Embodiment 2, as in Embodiment 1, for example, when the numberindicating the amount of the resources having been allocated to mobilestation 200 includes a prime factor different from one or more specificnumbers, controller 201 controls the transmission process on anassumption that the resources having been allocated to mobile station200 and the resources to which the uplink data signals are mapped aredifferent from each other.

For example, when the number of the allocation subcarriers includes aprime factor different from the specific numbers, controller 201 maychange at least one among the number and the positions of thesubcarriers to which the data signals are mapped and the number of thedata signals to a value different from that for the allocatedsubcarriers.

For example, controller 201 configures the number of the data signalsand further configures, from among the allocation subcarriers, thenumber of the mapping subcarriers to which the data signals are mappedwith a one-to-one correspondence. On that occasion, controller 201selects the configured number of the mapping subcarriers to be the sameas the number of the data signals. As described above, the number of thedata signals having been configured by controller 201 corresponds to thenumber of the data signals output from DFT section 203.

Then, controller 201 configures one or more subcarriers to which one ormore repetition data signals are mapped. The subcarriers to which therepetition data signals are mapped are, for example, at least part ofthe subcarriers among the allocation subcarriers except for the mappingsubcarriers. The subcarriers to which the repetition data signals aremapped are also referred to as duplicate mapping subcarriers in somecases.

In the above-described case, the data signals mapped to the mappingsubcarriers do not overlap with each other. On the other hand, the datasignals mapped to the duplicate mapping subcarriers overlap with any ofthe data signals mapped to the mapping subcarriers. Stated in anotherway, the data signals mapped to the mapping subcarriers are repeatedlymapped to the duplicate mapping subcarriers.

An example implemented according to Embodiment 2 is described below byreferring to the example of FIG. 8. For example, when the allocationresources illustrated in FIG. 8 are allocated to mobile station 200,controller 201 decides that the allocation resources are the interlaces#0 and #10. Then, controller 201 decides that the number of theallocation subcarriers is 204.

Then, controller 201 determines whether the number of the allocationsubcarriers includes a prime factor different from the specific numbers.In the case in which the specific numbers are 2, 3 and 5, for example,because the number of the allocation subcarriers is 204=2×2×3×17,controller 201 determines that the number of the allocation subcarriersincludes a prime factor, namely 17, different from 2, 3 and 5.

In the above-mentioned case, controller 201 in Embodiment 2 mayconfigure, as the number of the data signals and the number of themapping subcarriers, any one of numbers that are smaller than or equalto the number of the allocation subcarriers and that do not include anyprime factor different from the specific numbers (namely, that includeonly the specific numbers as prime factors thereof).

For example, a maximum one among numbers that are smaller than or equalto the number of the allocation subcarriers and that do not include anyprime factor different from the specific numbers may be configured asthe number of the data signals and the number of the mappingsubcarriers.

In the case of the above-described example, the number of the allocationsubcarriers is 204 and the specific numbers are 2, 3 and 5. In thatcase, the maximum one among the numbers that are smaller than or equalto the number of the allocation subcarriers and that do not include anyprime factor different from the specific numbers is 200 (=2³×5²).

In the above-described case, controller 201 configures the number of thedata signals and the number of the mapping subcarriers to 200 andfurther configures the number of the data signals mapped to thesubcarriers with a one-to-one correspondence to 200. Then, controller201 configures, as the duplicate mapping subcarriers, 4 subcarriersamong the number 204 of the allocation subcarriers except for the number200 of the mapping subcarriers. Controller 201 may configure, as theduplicate mapping subcarriers, part (for example, 1 to 3) among those 4subcarriers. In such a case, signals do not need to be mapped to thesubcarriers that have been not configured as the mapping subcarriers andthe duplicate mapping subcarriers.

Controller 201 configures the positions of the mapping subcarriers andthe positions of the duplicate mapping subcarriers from among theallocation subcarriers. A method of configuring the positions of themapping subcarriers may be any one of Configuring Methods 1 to 5described in Embodiment 1. Instead, the mapping subcarriers may beconfigured arbitrarily (for example, at random).

Then, controller 201 configures, from among the data signals mapped tothe 200 mapping subcarriers with a one-to-one correspondence, the datasignals mapped to the duplicate mapping subcarriers.

For example, controller 201 may configure, as the data signals mapped tothe duplicate mapping subcarriers, first 4 data signals among the 200data signals that are output from DFT section 203 and that are mapped tothe mapping subcarriers.

Here, the first 4 data signals may be 4 data signals at the head of theoutput signals when the order of outputs from DFT section 203 isspecified. For example, since the DFT process is executed astime-frequency conversion, the specified order may be given in terms offrequency in the DFT process.

For example, when indexes #0 to #199 are assigned to the 200 datasignals output from DFT section 203, the data signals assigned with theindexes #0 to #3 correspond to the first 4 data signals.

For example, the data signals #0 to #199 are mapped in order startingfrom the subcarrier at the lowest frequency in the allocationsubcarriers, and the data signals #0 to #3 are then mapped repeatedly.Thus, in such a case, the data signals are mapped in order of #0 to #199and #0 to #3 starting from the lowest frequency in the allocationsubcarriers. A rise of PAPR can be suppressed by using theabove-mentioned method.

Controller 201 outputs, to signal assigner 204, the mapping resourceinformation including information that indicates the number and thepositions of the mapping subcarriers, the number and the positions ofthe duplicate mapping subcarriers, and the data signals mapped to theduplicate mapping subcarriers. Controller 201 further outputsinformation about the number of the uplink data signals, namelyinformation about the number of the mapping subcarriers, toencoder/modulator 202.

Encoder/modulator 202 executes error correction coding and modulation onthe uplink data in accordance with the number of the data signals andoutputs the resulting signals to DFT section 203. DFT section 203executes a DFT process (for example, a FFT process) on the signalsreceived from encoder/modulator 202 and outputs the resulting outputsignals to signal assigner 204. Here, since the number of the datasignals is a number not including any prime factor different from thespecific numbers (2, 3 and 5 in the above-described example), it ispossible to suppress an increase in the amount of computation executedin the DFT process (for example, the FFT process) by DFT section 203,and to increase the speed of the DFT process.

Signal assigner 204 maps the signals, received from DFT section 203, tothe mapping subcarriers in accordance with the positions of the mappingsubcarriers. Then, signal assigner 204 repeatedly maps the data signalsto the duplicate mapping subcarriers in accordance with the informationindicating the positions of the duplicate mapping subcarriers and thedata signals mapped to the duplicate mapping subcarriers.

Although detailed description is omitted, as with controller 201 inmobile station 200, controller 101 in base station 100 may change atleast one among the number and the positions of the mapping subcarriersand the number of the data signals to a value different from that in theallocation resource information. Information about a changing method maybe shared between mobile station 200 and base station 100. In such acase, mobile station 200 and base station 100 may change at least oneamong the number and the positions of the mapping subcarriers and thenumber of the data signals to a value different from that in theallocation resource information in accordance with the same changingmethod.

For example, IDFT section 108 receives, from signal separator 107, thesignals that have been mapped to the mapping subcarriers and that arethe same in number as the mapping subcarriers, executes an IDFT process(for example, a FFT process), and outputs the processed signals todemodulator/decoder 109. Furthermore, IDFT section 108 may receive, fromsignal separator 107, the signals that have been mapped to the duplicatemapping subcarriers, and may execute an interpolation process before orafter the IDFT process. Here, since the number of the data signals,namely the number of the mapping subcarriers, is a number not includingany prime factor different from the specific numbers (2, 3 and 5 in theabove-described example), it is possible to suppress an increase in theamount of computation executed in the IDFT process (for example, theIFFT process) by IDFT section 108, and to increase the speed of the IDFTprocess.

According to Embodiment 2, as described above, mapping subcarriers in anumber not including any prime factor different from one or morespecific numbers (2, 3 and 5 in the above-described example) areselected from among the allocation subcarriers, and the data signals inthe same number as the selected mapping subcarriers are mapped to thosemapping subcarriers with a one-to-one correspondence. Furthermore, thedata signals are repeatedly mapped to some subcarriers (duplicatemapping subcarriers) that are included in the allocation subcarriers andthat are different from the mapping subcarriers. It is hence possible tosuppress an increase in the amounts of computations executed in the DFTprocess and the IDFT process corresponding to the DFT process, and toefficiently utilize the resources. As a result, signals can beappropriately transmitted and received in the operation in theunlicensed band. In addition, since Occupied Channel Bandwidth (OCB) ofthe mapping subcarriers does not become narrower than the band of theallocation subcarriers, the possibility of violating the limitationstipulated by ETSI on OCB can be reduced.

Moreover, according to Embodiment 2, since part of the data signals isrepeatedly transmitted in the frequency domain, reliability of the datasignals can be improved.

Embodiment 3

Embodiment 1 and Embodiment 2 have been described in connection with theexample in which the number indicating the amount of the mappingresources is decided. Embodiment 3 is described below in connection withan example of the method of deciding the amount of the data signals (orthe number of the data signals) in a different manner from those inEmbodiment 1 and Embodiment 2.

An outline of a communication system, a configuration of a base station,a configuration of a mobile station, and an operation sequence inEmbodiment 3 are similar to those in Embodiment 1, and hence detaileddescription of those points is omitted. In the following, Embodiment 3is described by referring to the outline of the communication system,the configuration of the base station, and the configuration of themobile station, which have been described in Embodiment 1.

In Embodiment 3, as in Embodiment 1, for example, when the numberindicating the amount of the resources having been allocated to mobilestation 200 includes a prime factor different from one or more specificnumbers, controller 201 controls the transmission process on anassumption that the resources having been allocated to mobile station200 and the resources to which the uplink data signals are mapped aredifferent from each other.

For example, when the number of the allocation subcarriers includes aprime factor different from the specific numbers, controller 201 maychange at least one among the number and the positions of the mappingsubcarriers and the number of the data signals to a value different fromthat in the allocation resource information.

For example, controller 201 in Embodiment 3 may configure, as the numberof the data signals output from DFT section 203, any one of numbers thatare larger than or equal to the number of the allocation subcarriers (orlarger than the number of the allocation subcarriers) and that do notinclude any prime factor different from the specific numbers (namely,that include only the specific numbers as prime factors thereof). In thefollowing description, the data signals output from DFT section 203 arereferred to as “output data signals” in some cases.

For example, a minimum one among numbers that are larger than or equalto the number of the allocation subcarriers and that do not include anyprime factor different from the specific numbers may be configured asthe number of the output data signals.

Then, controller 201 outputs the mapping resource information includingthe configured number of the output data signals to signal assigner 204.Controller 201 further outputs information about the number of theoutput data signal to encoder/modulator 202.

Encoder/modulator 202 executes error correction coding and modulation onthe uplink data in accordance with the number of the output data signalsand outputs the resulting output signals to DFT section 203. The numberof the signals output to DFT section 203 corresponds to the number ofthe output data signals.

DFT section 203 executes a DFT process (for example, a FFT process) onthe signals received from encoder/modulator 202 and outputs theresulting output data signals to signal assigner 204. Here, since thenumber of the output data signals is a number not including any primefactor different from the specific numbers (for example, 2, 3 and 5), itis possible to suppress an increase in the amount of computationexecuted in the DFT process (for example, the FFT process) by DFTsection 203, and to increase the speed of the DFT process.

Signal assigner 204 maps the signals received from DFT section 203. InEmbodiment 3, the number of the signals received from DFT section 203,namely the number of the output data signals, is larger than the numberof the allocation subcarriers. Therefore, signal assigner 204 does notneed to map part of the signals received from DFT section 203.

As with controller 201 in mobile station 200, controller 101 in basestation 100 may change at least one among the number and the positionsof the mapping subcarriers and the number of the data signals to a valuedifferent from that in the allocation resource information. Informationabout a changing method may be shared between mobile station 200 andbase station 100. In such a case, mobile station 200 and base station100 may change at least one among the number and the positions of themapping subcarriers and the number of the data signals to a valuedifferent from that in the allocation resource information in accordancewith the same changing method.

An example implemented according to Embodiment 3 is described below byreferring to the example of FIG. 8. For example, when the allocationresources illustrated in FIG. 8 are allocated to mobile station 200,controller 201 decides that the allocation resources are the interlaces#0 and #10. Then, controller 201 decides that the number of theallocation subcarriers is 204.

Then, controller 201 determines whether the number of the allocationsubcarriers includes a prime factor different from the specific numbers.In the case in which the specific numbers are 2, 3 and 5, for example,because the number of the allocation subcarriers is 204=2×2×3×17,controller 201 determines that the number of the allocation subcarriersincludes a prime factor, namely 17, different from 2, 3 and 5.

In the case of the above-described example, the number of the allocationsubcarriers is 204 and the specific numbers are 2, 3 and 5. In thatcase, the minimum one among the numbers that are larger than or equal tothe number of the allocation subcarriers and that do not include anyprime factor different from the specific numbers is 216 (=2³×3³).

In the above-described case, controller 201 configures the number of theoutput data signals to 216. Then, controller 201 outputs the mappingresource information including the configured number of the output datasignals to signal assigner 204. Controller 201 further outputsinformation about the number of the output data signal toencoder/modulator 202.

In the case of the above-described example, the signals received fromDFT section 203, namely the 216 output data signals, are 12 more thanthe 204 allocation subcarriers. Therefore, signal assigner 204 does notneed to map at least 12 output data signals.

According to Embodiment 3, as described above, any one of the numbersthat are larger than or equal to the number of the allocationsubcarriers and that do not include any prime factor different from thespecific numbers (namely, that include only the specific numbers asprime factors thereof) is configured as the number of the data signalsoutput from DFT section 203. This method makes it possible to suppressan increase in the amounts of computations executed in the DFT processand the IDFT process corresponding to the DFT process, and toefficiently utilize the resources. As a result, signals can beappropriately transmitted and received in the operation in theunlicensed band. In addition, the above-mentioned method can realizeefficient use of the allocation subcarriers and can increase a transferspeed.

Embodiment 4

Embodiment 3 has been described in connection with the example in whichthe number of the output data signals is configured to be larger than orequal to the number of the allocation subcarriers and part of the outputdata signals output from DFT section 203 is not mapped to thesubcarriers. Embodiment 4 is described below in connection with anexample in which part of the output data signals output from DFT section203 is mapped to resources different from the allocation subcarriers.

An outline of a communication system, a configuration of a base station,a configuration of a mobile station, and an operation sequence inEmbodiment 4 are similar to those in Embodiment 1, and hence detaileddescription of those points is omitted. In the following, Embodiment 4is described by referring to the outline of the communication system,the configuration of the base station, and the configuration of themobile station, which have been described in Embodiment 1.

In Embodiment 4, as in Embodiment 3, controller 201 configures thenumber of the output data signals.

Then, controller 201 outputs the mapping resource information includingthe configured number of the output data signals to signal assigner 204.Controller 201 further outputs information about the number of theoutput data signal to encoder/modulator 202.

Encoder/modulator 202 executes error correction coding and modulation onthe uplink data in accordance with the number of the output data signalsand outputs the resulting signals to DFT section 203. The number of thesignals output to DFT section 203 corresponds to the number of theoutput data signals.

DFT section 203 executes a DFT process (for example, a FFT process) onthe signals received from encoder/modulator 202 and outputs theresulting output data signals to signal assigner 204. Here, since thenumber of the output data signals is a number not including any primefactor different from the specific numbers (for example, 2, 3 and 5), itis possible to suppress an increase in the amount of computationexecuted in the DFT process (for example, the FFT process) by DFTsection 203, and to increase the speed of the DFT process.

Signal assigner 204 maps the signals received from DFT section 203. InEmbodiment 4, as in Embodiment 3, the number of the signals receivedfrom DFT section 203, namely the number of the output data signals, islarger than the number of the allocation subcarriers. In Embodiment 4,signal assigner 204 maps part of the output data signals received fromDFT section 203 to resources different from the allocation subcarriers.In the following description, the output data signals mapped to theresources different from the allocation subcarriers are also referred toas extra data signals in some cases. The extra data signals correspondto at least part or all of the output data signals that are not mappedto the allocation subcarriers.

For example, the extra data signals may be mapped to resources that arenot allocated to mobile station 200. Selection of the resources notallocated to mobile station 200 may be executed by, for example,controller 201.

For example, controller 201 may select some subcarriers in the samenumber as the extra data signals from among subcarriers positionedbetween the allocation subcarriers. Information indicating the positionsof the selected subcarriers may be included in the mapping resourceinformation and output to signal assigner 204. Information about amethod of selecting the subcarriers may be made known in mobile station200 and base station 100 in advance or may be indicated from basestation 100 to mobile station 200. Instead, the information about themethod of selecting the subcarriers and/or the information indicatingthe positions of the selected subcarriers may be indicated from mobilestation 200 to base station 100.

In the above-mentioned case, signal assigner 204 may map the extra datasignals to the selected subcarriers in accordance with the mappingresource information.

As with controller 201 in mobile station 200, controller 101 in basestation 100 may change at least one among the number and the positionsof the mapping subcarriers and the number of the data signals to a valuedifferent from that in the allocation resource information. Informationabout a changing method may be shared between mobile station 200 andbase station 100. In such a case, mobile station 200 and base station100 may change at least one among the number and the positions of themapping subcarriers and the number of the data signals to a valuedifferent from that in the allocation resource information in accordancewith the same changing method.

An example implemented according to Embodiment 4 is described below byreferring to the example of FIG. 8. For example, when the allocationresources illustrated in FIG. 8 are allocated to mobile station 200,controller 201 configures the number of the output data signals to 216as in the example described in Embodiment 3.

In the case of the above-described example, the signals received fromDFT section 203, namely the 216 output data signals, are 12 more thanthe 204 allocation subcarriers. Therefore, signal assigner 204 maps atleast 12 extra data signals to resources different from the allocationsubcarriers.

According to Embodiment 4, as described above, any one of the numbersthat are larger than or equal to the number of the allocationsubcarriers and that do not include any prime factor different from thespecific numbers (namely, that include only the specific numbers asprime factors thereof) is configured as the number of the data signalsoutput from DFT section 203. This method makes it possible to suppressan increase in the amounts of computations executed in the DFT processand the IDFT process corresponding to the DFT process, and toefficiently utilize the resources. As a result, signals can beappropriately transmitted and received in the operation in theunlicensed band. In addition, the above-mentioned method can realizeefficient use of the allocation subcarriers and can increase a transferspeed.

Furthermore, according to Embodiment 4, the data signals output from DFTsection 203 can be all transmitted by using, in addition to theallocation resources, the resources that are not allocated to mobilestation 200. Hence the transfer speed can be improved, and the signaltransmission can be performed with high reliability.

Embodiment 4 has been described above in connection with the example inwhich the resources to which the extra data signals are mapped areselected in units of subcarriers. Since the resources are selected inunits of subcarriers, the resources for use in the signal transmissioncan be configured flexibly.

In Embodiment 4, the resources to which the extra data signals aremapped may be selected in units of PRBs.

For example, controller 201 may select, from among PRBs positionedbetween PRBs making up the allocation resources, some PRBs in amountenough to allow mapping of the extra data signals thereto. Informationindicating positions of the selected PRBs may be included in the mappingresource information and output to signal assigner 204.

Thus, since the resources to which the extra data signals are mapped areselected in units of RPBs, the signal transmission and receptionprocesses can be executed in units of RPBs and hence easier installationcan be realized.

Embodiment 5

Embodiment 5 is described below in connection with an example in whichany one of the above-described methods according to Embodiments 1 to 4is used depending on the number of the allocation subcarriers, forexample. It is to be noted that description of the methods alreadydescribed in Embodiments 1 to 4 is omitted as appropriate.

An outline of a communication system, a configuration of a base station,a configuration of a mobile station, and an operation sequence inEmbodiment 5 are similar to those in Embodiment 1, and hence detaileddescription of those points is omitted. In the following, Embodiment 5is described by referring to the outline of the communication system,the configuration of the base station, and the configuration of themobile station, which have been described in Embodiment 1.

In Embodiment 5, as in Embodiment 1 and so on, for example, when thenumber indicating the amount of the resources having been allocated tomobile station 200 includes a prime factor different from one or morespecific numbers, controller 201 controls the transmission process on anassumption that the resources having been allocated to mobile station200 and the resources to which the uplink data signals are mapped aredifferent from each other.

For example, when the number of the allocation subcarriers includes aprime factor different from the specific numbers, controller 201 maychange at least one among the number and the positions of the mappingsubcarriers and the number of the data signals to a value different fromthat in the allocation resource information.

For example, controller 201 in Embodiment 5 may configure, as the numberof the output data signals output from DFT section 203, one of numbersthat do not include any prime factor different from the specific numbers(namely, that include only the specific numbers as prime factorsthereof), the one number being closest to the number of the allocationsubcarriers.

For example, when the configured number of the output data signals issmaller than or equal to the number of the allocation subcarriers,controller 201 decides, from among the allocation subcarriers, themapping subcarriers to which the output data signals are mapped, as inEmbodiments 1 and 2.

In the above-mentioned case, as in Embodiment 1, those ones of theallocation subcarriers, which are not included in the mappingsubcarriers, do not need to be used. Instead, as in Embodiment 2, theoutput data signals may be repeatedly mapped to those ones of theallocation subcarriers, which are not included in the mappingsubcarriers.

As another example, when the configured number of the output datasignals is larger than or equal to the number of the allocationsubcarriers, controller 201 maps, to the allocation subcarriers, theoutput data signals in the same number as the allocation subcarrierslike Embodiments 3 and 4.

In the above-mentioned case, as in Embodiment 3, the output data signals(the extra data signals) not mapped to the allocation subcarriers may beexcluded. Instead, as in Embodiment 4, the output data signals (theextra data signals) not mapped to the allocation subcarriers may bemapped to other resources than being allocated.

An example implemented according to Embodiment 5 is described below byreferring to the example of FIG. 8. For example, when the allocationresources illustrated in FIG. 8 are allocated to mobile station 200,controller 201 decides that the allocation resources are the interlaces#0 and #10. Then, controller 201 decides that the number of theallocation subcarriers is 204.

Then, controller 201 configures the number of the output data signals to200 for the reason that the number closest to the number of theallocation subcarriers among the numbers not including any prime factordifferent from the specific numbers (2, 3 and 5) is 200 (=2³×5²).

In the above-mentioned case, since the configured number of the outputdata signals is smaller than the number of the allocation subcarriers,controller 201 decides, from among the allocation subcarriers, themapping subcarriers to which the output data signals are mapped, as inEmbodiments 1 and 2. Furthermore, as in Embodiment 1, those ones of theallocation subcarriers, which are not included in the mappingsubcarriers, do not need to be used. Instead, as in Embodiment 2, theoutput data signals may be repeatedly mapped to those ones of theallocation subcarriers, which are not included in the mappingsubcarriers.

According to Embodiment 5, as described above, any one of theabove-described methods according to Embodiments 1 to 4 is useddepending on the number of the allocation subcarriers. Those methodsmake it possible to suppress an increase in the amounts of computationsexecuted in the DFT process and the IDFT process corresponding to theDFT process, and to efficiently utilize the resources. As a result,signals can be appropriately transmitted and received in the operationin the unlicensed band. In addition, those methods can suppress areduction in the frequency utilization rate of the allocationsubcarriers and a fall of the transfer speed. Moreover, those methodscan suppress not only an increase in usage rate of the resources thatare not allocated, but also degradation of reliability in transmissionand reception of the signals.

Other Embodiment 1

Embodiment 1 to 5 have been described above in connection the example ofthe interlace configuration in which the numbers assigned to theinterlaces with a larger value of N are smaller than the numbersassigned to the interlaces with a smaller value of N. In the interlaceconfiguration illustrated in FIG. 2, for example, the numbers assignedto the interlaces of N=8 are 0 to 9 while the numbers assigned to theinterlaces of N=9 are 10 and 11. The present disclosure is not limitedto that example. Other Embodiment 1 is described below in connectionwith an example in which the interlace configuration is different fromthat illustrated in FIG. 2.

FIG. 9 illustrates another example of the interlace configuration inNR-U. FIG. 9 represents an example in which M and N indicating theinterlace configuration are given by (M, N)=(10, 10 or 11).

In FIG. 9, numbers 0, 1, 3, 4, 6 and 7 are assigned to the interlaces ofN=11 (namely, the interlaces each including 11 PRBs), and numbers 2, 5,8 and 9 are assigned to the interlaces of N=10 (namely, the interlaceseach including 10 PRBs).

The following description is made, by way of example, in connection withthe case in which controller 101 in base station 100 allocates threeinterlaces to mobile station 200 in accordance with the interlaceconfiguration illustrated in FIG. 9. In that case, it may be assumed toadopt an allocation method of allocating the interlaces assigned withconsecutive numbers to mobile station 200. Under such an assumption, theinterlaces assigned with three consecutive numbers (for example,interlaces #0, #1 and #2) in the interlace configuration illustrated inFIG. 9 are assigned to mobile station 200.

For example, when the interlaces #0, #1 and #2 are assigned to mobilestation 200, the number of PRBs in the allocation resources allocated tomobile station 200 is 32 in total. Because one PRB includes 12subcarriers, the number of the allocation subcarriers allocated tomobile station 200 is 384 (=×3). In this case, the number of theallocation subcarriers assigned to mobile station 200 is a number notincluding any prime factor different from 2, 3 and 5.

According to Other Embodiment 1, as described above, configuring of thenumbers assigned to the interlaces is changed in accordance with boththe interlace allocation method in base station 100 and the interlaceconfiguration. Such a method makes it possible to suppress an increasein the amounts of computations executed in the DFT process and the IDFTprocess corresponding to the DFT process. In addition, the allocationsubcarriers can be efficiently used, and the transfer speed can beincreased.

Other Embodiment 2

Embodiment 1 has been described above in connection with the example inwhich the interlaces are arranged to be distributed by arranging PRBs atequal spacings. The present disclosure is not limited to that example,and the interlace configuration may be changed. Other Embodiment 2 isdescribed below in connection with an example in which the interlaceincludes resources given in a unit other than PRB.

FIG. 10 illustrates an example of an interlace configuration accordingto Other Embodiment 2. FIG. 10 represents the example of the interlaceconfiguration in which it is assumed that the maximum assignment numberof PRBs is 106 and M=12 is configured. In the example illustrated inFIG. 10, a subcarrier group (namely, PRB) including 12 subcarriers isarranged in a lower frequency range. Furthermore, a subcarrier groupincluding 8 subcarriers is arranged in a higher frequency range. In thefollowing description, the subcarrier group including 8 subcarriers isalso referred to as a sub-PRB in some cases.

In the case of the interlace configuration illustrated in FIG. 10, sinceone interlace includes 8 PRBs and 1 sub-PRB, one interlace includes 96subcarriers. For example, when one interlace is allocated to mobilestation 200, the number of the allocation subcarriers is a number notincluding any prime factor different from the specific numbers (2, 3 and5).

Furthermore, when two or more interlaces except for 7 and 11 interlacesare allocated, the number of the allocation subcarriers is also a numbernot including any prime factor different from the specific numbers (2, 3and 5) as in the case of allocating one interlace.

According to Other Embodiment 2, as described above, the unit of theresources in the interlace configuration is changed. Such a change makesit possible to suppress an increase in the amounts of computationsexecuted in the DFT process and the IDFT process corresponding to theDFT process. In addition, the allocation subcarriers can be efficientlyused, and the transfer speed can be increased.

Other Embodiment 2 has been described in connection with the example inwhich the unit of the resources arranged in the lower frequency range isPRB and the unit of the resources arranged in the higher frequency rangeis sub-PRB. In another example, the unit of the resources arranged inthe higher frequency range may be PRB, and the unit of the resourcesarranged in the lower frequency range may be sub-PRB. In still anotherexample, PRB and sub-PRB may be arranged in mixed order without beingconcentratedly distributed to separate ranges in the frequency domain.

Furthermore, Other Embodiment 2 has been described in connection withthe example in which the unit of part of the resources is PRB and theunit of the remaining resources is sub-PRB. In another example, the unitof all the resources may be defined by sub-PRB. Instead, the units ofthe resources may be defined by a plurality of subcarrier groupsincluding the different numbers of the subcarriers. For example, asubcarrier group including 8 subcarriers and a subcarrier groupincluding 6 subcarriers may be defined as the units of the resources.

In the above embodiments, when any part of the interlaces in the mappingresources is a subcarrier group (for example, sub-PRB) including two ormore subcarriers and/or a single subcarrier, a method of arranging apilot signal (for example, a channel estimation reference signal andDemodulation Reference Signal (DMRS)) in the resource corresponding tothe above-mentioned part may be the same as a method of arranging apilot signal in the case of PRB. Instead, the pilot signal does not needto be arranged in the resource corresponding to the above-mentionedpart.

The methods described in the above embodiments may be used alone or incombination. Instead, the method to be used may be switched overdepending on situations (for example, communication environment and/ortraffic volume). The communication environment may be expressed by atleast one of Reference Signal Received Power (RSRP), Received SignalStrength Indicator (RSSI), Reference Signal Received Quality (RSRQ), andSignal-to-Interference plus Noise power Ratio (SINR), or by any one ofother suitable parameters. The traffic volume may be expressed by, forexample, at least one of the number of the mobile stations connected tothe base station, the amount of data transmitted from the mobilestation, and the amount of resources that can be allocated to the mobilestation, or by any one of other suitable parameters.

While the above embodiments have been described in connection with theexample in which the mobile station and the base station adjust (change)the number of the mapping resources and the number of the data signalsto be transmitted and received, the present disclosure is not limited tothat example.

For example, whether to perform the adjustment and/or the method for theadjustment may be previously determined in the form of standards. Forexample, both the base station and the mobile station may recognize thesame method individually and may perform the adjustment by the samemethod.

In another example, the above-mentioned points may be explicitly orimplicitly indicated from the base station to the mobile station byusing the higher layer signal and/or DCI, for example. The mobilestation may perform the adjustment in accordance with the indicationfrom the base station. When the above-mentioned points are implicitlyindicated, the numbers indicating the allocation resources and/or theinterlaces may be used to implicitly indicate the method for theadjustment, for example.

Instead, the mobile station may perform the adjustment and mayexplicitly or implicitly indicate, to the base station, informationindicating the result of the adjustment by using, for example, thehigher layer signal and/or UCI (Uplink Control Signal). In such a case,the base station may perform the adjustment in accordance with theindication from the mobile station.

While the operation examples in the above embodiments have beendescribed on an assumption of using the DFT process in the mobilestation, the present disclosure is not limited to such a case. Forexample, the interlace mapping may be realized with the signal waveformbased on CP-OFDM (Cyclic Prefix-Orthogonal Frequency DivisionMultiplexing).

The above embodiments have been described on an assumption of applyingthe present disclosure to the uplink in which the mobile stationcorresponds to a transmitter and the base station corresponds to areceiver. In another example, the present disclosure may be applied tothe downlink in which the base station corresponds to a transmitter andthe mobile station corresponds to a receiver. In still another example,the present disclosure may be applied to a radio communication link (forexample, the so-called sidelink) that is established in communicationbetween mobile stations (for example, vehicle-to-vehicle communication).In that case, the mobile stations performing the communicationcorrespond to a transmitter and a receiver. The present disclosure maybe further applied to other types of communication and so on withoutlimited to the above-mentioned cases.

The expressions “ . . . section”, “ . . . er” and “ . . . or” used todenote the constituent elements of base station 100 and mobile station200 in the above embodiments may be replaced with other expressions suchas “ . . . circuitry”, “ . . . device”, “ . . . unit” or “ . . .module”.

Furthermore, the expressions “specify”, “decide”, “configure”,“determine”, and “assume” used in the description of the aboveembodiments may be read changeably.

The term “higher layer signal” used in the description of the aboveembodiments may be replaced with a different word such as “RRC (RadioResource Control signaling) signal”.

The acronym “DFT” used in the description of the above embodiments maybe replaced with a term such as “Discrete Fourier Transform” or“Transform Precoding”.

The acronym “FFT” used in the description of the above embodiments maybe replaced with a term such as “Fast Fourier Transform” or “TransformPrecoding”.

The acronym “IDFT” used in the description of the above embodiments maybe replaced with a term such as “Inverse Discrete Fourier Transform”.

The acronym “IFFT” used in the description of the above embodiments maybe replaced with a term such as “Inverse Fast Fourier Transform”.

The resource band width, the number of the subcarriers, the number ofPRBs, and so on, which are specified in the frequency domain in theabove embodiments, are merely examples, and the present disclosure isnot limited to those examples. Moreover, the expressions, such as“subcarrier”, “PRB”, and “sub-PRB”, used to specify the unit fordividing the resources are merely examples and may be replaced withother suitable expressions.

The various embodiments have been described above.

The present disclosure can be realized by software, hardware, orsoftware in cooperation with hardware.

Each functional block used in the description of each embodimentdescribed above can be partly or entirely realized by an LSI such as anintegrated circuit, and each process described in the each embodimentmay be controlled partly or entirely by the same LSI or a combination ofLSIs. The LSI may be individually formed as chips, or one chip may beformed so as to include a part or all of the functional blocks. The LSImay include a data input and output coupled thereto. The LSI here may bereferred to as an IC, a system LSI, a super LSI, or an ultra LSIdepending on a difference in the degree of integration.

However, the technique of implementing an integrated circuit is notlimited to the LSI and may be realized by using a dedicated circuit, ageneral-purpose processor, or a special-purpose processor. In addition,a FPGA (Field Programmable Gate Array) that can be programmed after themanufacture of the LSI or a reconfigurable processor in which theconnections and the settings of circuit cells disposed inside the LSIcan be reconfigured may be used. The present disclosure can be realizedas digital processing or analogue processing.

If future integrated circuit technology replaces LSIs as a result of theadvancement of semiconductor technology or other derivative technology,the functional blocks could be integrated using the future integratedcircuit technology. Biotechnology can also be applied.

The present disclosure can be realized by any kind of apparatus, deviceor system having a function of communication, which is referred to as acommunication apparatus. Some non-limiting examples of such acommunication apparatus include a phone (e.g, cellular (cell) phone,smart phone), a tablet, a personal computer (PC) (e.g, laptop, desktop,netbook), a camera (e.g, digital still/video camera), a digital player(digital audio/video player), a wearable device (e.g, wearable camera,smart watch, tracking device), a game console, a digital book reader, atelehealth/telemedicine (remote health and medicine) device, and avehicle providing communication functionality (e.g., automotive,airplane, ship), and various combinations thereof.

The communication apparatus is not limited to be portable or movable,and may also include any kind of apparatus, device or system beingnon-portable or stationary, such as a smart home device (e.g, anappliance, lighting, smart meter, control panel), a vending machine, andany other “things” in a network of an “Internet of Things (IoT)”.

The communication may include exchanging data through, for example, acellular system, a wireless LAN system, a satellite system, etc., andvarious combinations thereof.

The communication apparatus may comprise a device such as a controlleror a sensor which is coupled to a communication device performing afunction of communication described in the present disclosure. Forexample, the communication apparatus may comprise a controller or asensor that generates control signals or data signals which are used bya communication device performing a communication function of thecommunication apparatus.

The communication apparatus also may include an infrastructure facility,such as a base station, an access point, and any other apparatus, deviceor system that communicates with or controls apparatuses such as thosein the above non-limiting examples.”

A mobile station according to one exemplary embodiment of the presentdisclosure includes: transmission circuitry, which, in operation,transmits uplink signals; and control circuitry, which, in operation,when a first number indicating an amount of first resources usable intransmitting the uplink signals includes, as a prime factor, a thirdnumber different from a specific second number, controls transmission ofa fourth number of signals, the transmission being performed usingsecond resources, the fourth number not including the third number as aprime factor.

The mobile station according to one exemplary embodiment of the presentdisclosure further includes: a discrete Fourier transformer, which inoperation, executes discrete Fourier transform of modulated signals, andoutputs the modulated signals after being transformed; and signalassignment circuitry, which in operation, performs mapping of themodulated signals after being transformed to the second resources, andoutputs the uplink signals, in which: the control circuitry configures anumber of the modulated signals as the fourth number and furtherconfigures the second resources based on the first number and the fourthnumber.

In the mobile station according to one exemplary embodiment of thepresent disclosure, when the first number is larger than the fourthnumber, the control circuitry configures, as the second resources,resources obtained by excluding third resources from the firstresources.

In the mobile station according to one exemplary embodiment of thepresent disclosure, the control circuitry configures at least part ofthe third resources as one or more resources that are used to repeatedlytransmit the signals.

In the mobile station according to one exemplary embodiment of thepresent disclosure, the control circuitry configures, as the thirdresources, one or more resources that are positioned in at least one ofa highest frequency band and a lowest frequency band among the firstresources.

In the mobile station according to one exemplary embodiment of thepresent disclosure, the control circuitry configures, as the thirdresources, one or more resources that are not positioned in a highestfrequency band and a lowest frequency band among the first resources.

In the mobile station according to one exemplary embodiment of thepresent disclosure, the control circuitry configures part of resourcesas the third resources, the part being positioned at a predeterminedspacing among the first resources along a frequency axis.

In the mobile station according to one exemplary embodiment of thepresent disclosure, when the first number is smaller than the fourthnumber, the control circuitry configures the first resources as thesecond resources that are used to transmit signals obtained by excludingat least part of the fourth number of the signals.

In the mobile station according to one exemplary embodiment of thepresent disclosure, the control circuitry configures resources differentfrom the first resources as resources that are used to transmit thesignals having been excluded.

In the mobile station according to one exemplary embodiment of thepresent disclosure, the control circuitry decides the second resourcesin units of subcarriers or units of subcarrier groups.

In the mobile station according to one exemplary embodiment of thepresent disclosure, the control circuitry decides the second resourcesin units of physical resource blocks.

In the mobile station according to one exemplary embodiment of thepresent disclosure, the control circuitry decides, as the fourth number,one among numbers that include the second number as a prime factor andthat do not include the third number as a prime factor, the one numberbeing closest to the first number, and executes a different transmissionprocess between when the first number is larger than the fourth numberand when the first number is smaller than the fourth number.

A base station according to one exemplary embodiment of the presentdisclosure includes: reception circuitry, which, in operation, receivesuplink signals; and control circuitry, which, in operation, when a firstnumber indicating an amount of first resources usable in transmittingthe uplink signals includes, as a prime factor, a third number differentfrom a specific second number, controls reception of a fourth number ofsignals, the reception being performed using second resources, thefourth number not including the third number as a prime factor.

The base station according to one exemplary embodiment of the presentdisclosure further includes: signal separation circuitry, which, inoperation, separates signals having been mapped to the second resources;and inverse discrete Fourier transform circuitry, which, in operation,executes discrete inverse Fourier transform of the signals having beenseparated, and outputs output signals; in which: the control circuitryconfigures a number of the output signals as the fourth number andfurther configures the second resources based on the first number andthe fourth number.

A transmission method according to one exemplary embodiment of thepresent disclosure includes: configuring, when a first number indicatingan amount of first resources usable in transmitting uplink signalsincludes, as a prime factor, a third number different from a specificsecond number, the fourth number not including the third number as aprime factor; and controlling transmission of the fourth number ofsignals, the transmission being performed using second resources.

A reception method according to one exemplary embodiment of the presentdisclosure includes: configuring, when a first number indicating anamount of first resources usable in transmitting uplink signalsincludes, as a prime factor, a third number different from a specificsecond number, a fourth number not including the third number as a primefactor; and controlling reception of the fourth number of signals, thereception being performed using second resources.

A base station according to one exemplary embodiment of the presentdisclosure includes: reception circuitry, which, in operation, receivesuplink signals; and control circuitry, which, in operation, decidesfirst resources usable in transmitting the uplink signals, and controlsa reception process of the uplink signals, the reception process beingperformed using the first resources, in which: the first resources haveone or more bands positioned at a predetermined spacing among aplurality of bands that are obtained by dividing a predeterminedfrequency band, and the control circuitry configures the one or morebands in the first resources such that a number indicating an amount ofresources included in the first resources does not include, as a primefactor, a third number different from a specific second number.

A mobile station according to one exemplary embodiment of the presentdisclosure includes: transmission circuitry, which, in operation,transmits signals; and control circuitry, which, in operation, controlsa transmission process of the signals, the transmission process beingperformed using usable first resources, in which: the first resourceshave one or more bands positioned at a predetermined spacing among aplurality of bands that are obtained by dividing a predeterminedfrequency band, at least part of the plurality of bands has a differentband width from remaining part, and a number indicating an amount ofresources included in the first resources does not include, as a primefactor, a third number different from a specific second number.

The disclosure of Japanese Patent Application No. 2018-206872, filed onNov. 1, 2018, including the specification, drawings and abstract, isincorporated herein by reference in its entirety.

INDUSTRIAL APPLICABILITY

An example of the present disclosure is advantageously applied to amobile communication system.

REFERENCE SIGNS LIST

-   100 Base station-   101, 201 Controller-   102, 202 Encoder/modulator-   103, 204 Signal assigner-   104, 205 Transmitter-   105, 206 Antenna-   106, 207 Receiver-   107, 208 Signal separator-   108 IDFT section-   109, 209 Demodulator/decoder-   200 Mobile station-   203 DFT section

1.-18. (canceled)
 19. A communication apparatus, comprising: a receiver,which, in operation, receives resource assignment information indicatinga set of one or more interlace indices; and a transmitter, which, inoperation, transmits an uplink signal on first resource blocks (RBs)within a band, wherein, a number of the first RBs is the largest integerwhich is not greater than a number of second RBs indicated by the set ofone or more interlace indices and which is based on one or more specificprime numbers.
 20. The communication apparatus according to claim 19,wherein the first RBs is the lowest RBs among the second RBs indicatedby the set of one or more interlace indices.
 21. The communicationapparatus according to claim 19, wherein each of the interlace indicesindicates a plurality of RBs arrayed at an equal spacing in a frequencydomain.
 22. The communication apparatus according to claim 19, whereinthe resource assignment information indicates the set of one or moreinterlace indices, which is selected from a plurality of sets includinga set of two or more interlace indices.
 23. The communication apparatusaccording to claim 19, wherein a size of the uplink signal is determinedbased on the first RBs.
 24. The communication apparatus according toclaim 19, wherein each of the interlace indices indicates a differentnumber of RBs.
 25. The communication apparatus according to claim 19,wherein the one or more specific prime numbers are one or more of two,three and five.
 26. The communication apparatus according to claim 19,wherein the resource assignment information is indicated by downlinkcontrol information (DCI).
 27. A communication method, comprising:receiving resource assignment information indicating a set of one ormore interlace indices; and transmitting an uplink signal on firstresource blocks (RBs) within a band, wherein, a number of the first RBsis the largest integer which is not greater than a number of second RBsindicated by the set of one or more interlace indices and which is basedon one or more specific prime numbers.
 28. The communication methodaccording to claim 27, wherein the first RBs is the lowest RBs among thesecond RBs indicated by the set of one or more interlace indices. 29.The communication method according to claim 27, wherein each of theinterlace indices indicates a plurality of RBs arrayed at an equalspacing in a frequency domain.
 30. The communication method according toclaim 27, wherein the resource assignment information indicates the setof one or more interlace indices, which is selected from a plurality ofsets including a set of two or more interlace indices.
 31. Thecommunication method according to claim 27, wherein a size of the uplinksignal is determined based on the first RBs.
 32. The communicationmethod according to claim 27, wherein each of the interlace indicesindicates a different number of RBs.
 33. The communication methodaccording to claim 27, wherein the one or more specific prime numbersare one or more of two, three and five.
 34. The communication methodaccording to claim 27, wherein the resource assignment information isindicated by downlink control information (DCI).